Flat strips of electrically conductive material, such as relatively soft copper, are used in numerous applications in which it is desired to provide an electrical bond between conductors, such as for grounding purposes. For example, in an underground vault for telephone equipment, it is common to provide thin strips of bonding ribbon which connect underground telephone cables to a grounding system located at the side of the vault. It is often necessary to join two bonding ribbons together, both mechanically and electrically. While clamps have been used to form the mechanical connection, it has been generally necessary to weld or solder together the pairs of bonding ribbons in order to form a sufficient electrical connection.
Further, it is often necessary to provide a ground connection between the bonding ribbons and a grounding system, typically through connection to an electrical conductor comprising part of the grounding system. The electrical conductor has generally been a ground wire or ground ribbon. While clamps have been used to form the mechanical connection to the electrical conductor, it has been generally necessary to weld or solder together the bonding ribbons to the electrical conductor in order to form a sufficient ground connection.
In an underground vault, the soldering of bonding ribbons to each other or to a ground wire or ribbon is dangerous and undesired in that the telephone cables are nitrogen filled, and this gas along with other gases which accumulate in an underground vault can be explosive. In addition, welding or soldering requires specialized equipment and skilled labor in order to form the necessary electrical connection between the bonding ribbons.
When bonding conductors are to be subjected to adverse conditions, the flat conductors may be painted or treated with a protective coating or coated with another layer of metal to provide for long-term life. For example, copper grounding straps may be provided with a pre-tinned top layer. To form an adequate electrical connection, it is necessary to penetrate any layers of dirt, paint and other non-conducting surfaces, as well as corrosion, to provide the necessary electrical connection to the base metal. Any clamp must also be able to maintain a suitable mechanical and electrical connection which will withstand the rigors of the environment in which it is to be used.
Known clamping devices for relatively flat materials have not been suitable for clamping together, both mechanically and electrically, a pair of bonding ribbons or other flat conductive materials without requiring soldering or the like which is undesirable in a number of applications. It is further desirable that any clamping device be of simple construction and relatively low cost. These desirable attributes have not been found in a single device which can also eliminate the need for soldering in underground vaults and other environments in which known methods of forming an electrical bonding connection are unsuitable.